The 31-year-old agreed a move to Oakwell weeks ago but a transfer embargo has delayed the move but the move has been completed this evening.
Simon Davey said to Barnsley player:
"I am absolutely delighted to have finally brought Andy into the Club and it is the one deal we have been waiting for.
"It has taken a while to complete through no fault of ours but all that is finished and Andy is now in with the squad and we cannot wait to begin working with him.
"Andy is a proven striker at Championship level and will bring a lot of experience and hopefully goals to compliment the forward players we have at the Club already. Andy brings something a little different and will make us a more potent attacking threat this season".
He will be in the squad to face Leicester City at the Walkers Stadium tomorrow.